This is a double-blind, randomized, comparative study to evaluate the safety, tolerability, and efficacy of L-743,872, a new echinocandin antifungal, versus amphotericin B in the treatment of fluconazole- unresponsive oropharyngeal and esophageal candidiasis. Patients will be randomized to doses of L-743,872 of 35 mg/day, 50 mg/day, and 70 mg/day or amphotericin B at 0.5 mg/kg day. All patients will receive either: (1) L-743,872 and placebo to amphotericin B or (2) amphotericin B and placebo to L-743,872. L-743,872 or matching placebo will be given intravenously as a single daily dose infused over a 1 hour period. This will be followed by amphotericin B or matching placebo given intravenously as a single daily dose infused over a 2 hour period. On Day 1, a test dose (1 mg) of amphotericin B/amphotericin B placebo will be given prior to the first therapeutic dose of amphotericin B placebo to determine the need for premedication prior to subsequent doses.